You are going to have a great time. Italy is a really great country to visit (haven't been to one that's bad) and there is sooo much to see. I happened to be in Rome during the last World Cup when they beat France, it was truly and amazing experience. I second the recommendations to go to Capri and Pompeii if you can, Capri is very beautiful and Pompeii is very interesting. Overall, I think Venice was my favorite city but Florence was in a very close second. If you can make a day visit to Assisi, the Basilica and town are very interesting. Definetly make a visit to the Vatican if you can too, it's pretty stunning. Venice at night is also a must if you aren't physically staying in Venice. There was a pretty fun place near Venice (about 30 min away on the "mainland") called Lido de Jesolo, the main street shutsdown at night and there were lots of bars, etc, its kind of a place where people from other places in Europe go on holiday, kinda fun, but touristy, nice, clean beach as well. If you are ever on the road and need a quick bite the Autogrills are pretty good (kind of pricey I suppose), they are kind of like an extremely uptown grocery, food, gas type deal, hard to explain, but the food was good (better than eating American at a McDonalds or something). You'll have such a good trip, I wish I could go back to Italy, there's just so much to see. Take lots of pictures and keep a log of what you eat, do, see, etc. If you are able to do anything after school finishes, a trip to Greece would be great, its a very fun and interesting country with lots to see also.
I second everything said by everyone else, except catch the baby if a gypsie throws it at you, your wallet isn't worth a childs life, especially if you keep all the good stuff (money, passport, credit card, id) in a money belt deal.
